As is well known in the art, personal portable networking devices (such as wireless personal digital assistants and network appliances) are becoming increasingly popular. As the number of such devices increases, the number of new applications running on these portable devices is also increasing. These portable devices require, in addition to traditional client-type applications such as Web browsing, server-type applications, e.g., server programs running on the user's device.
However, using the conventional networked-computing model, which is commonly referred as the “client-server” model, it is relatively difficult for a service provider to support large scale server-type computing to subscribers for a variety of reasons. For example, the private Internet Protocol (IP) addresses assigned to server devices located behind a firewall are invisible to clients located outside the firewall. In addition, even if the service provider can assign public Internet Protocol version 4 (IPv4) addresses to server devices behind the firewall, the service provider may not have enough such addresses to maintain a sufficient number of connections across the firewall simultaneously. Further, the conventional “client-server” model is server-centric and is effective at supporting a few well-known applications, each identified by a well-known port number.
For personal server-type applications, which may be of high diversity and not well known, it is inconvenient to associate each of these applications with a fixed port number. Also, although secure versions of various protocols have been developed for the purpose of protecting communications privacy, an eavesdropper can still determine the type of communications that are flowing between a client and a server by observing the well-known server port number.
It would, therefore, be desirable to provide a protocol that overcomes the aforesaid and other disadvantages.